Early Formation Research Articles

Addressing the urban congestion challenge based on traffic bottlenecks.

Historically, urban congestion and street life quality depended on city network hierarchies, shaped by land use and street layout. Yet navigation apps have shifted focus to travel time as the key route selection factor, challenging traditional urban structures. We review the development of an innovative approach to urban traffic management that leverages real-time data for the identification and analysis of traffic bottlenecks. This approach, combined with urban planning, aims to improve traffic flow and tackle modern urban challenges. It includes real-time bottleneck detection and cost, congestion analysis and designing a decentralized traffic management system that can serve planners. Based on complex system principles, it promises dynamic traffic optimization, merging urban planning with digital advancements. The research demonstrates the potential of different applications of the proposed methodologies to predict significant congestion from early bottleneck formation, offering urban planners a powerful toolset for reasserting their role in shaping the urban experience. This article posits that a nuanced understanding of traffic dynamics, coupled with advanced traffic management technologies, can restore the influence of urban planning in the digital era, fostering more liveable, equitable and efficient urban environments. This article is part of the theme issue 'Co-creating the future: participatory cities and digital governance'.

Prevention of early thrombosis in transplanted vein model by encapsulation with tirofiban microneedle drug delivery system.

Early thrombosis following CABG surgery leads to perioperative myocardial infarction, which causes difficulties for clinicians and patients. Moreover, once perioperative myocardial infarction occurs, the mortality rate is extremely high. In recent years, microneedle (MN) drug delivery systems have become a research hotspot with broad clinical application prospects. These systems are capable of achieving sustained, safe, and painless local drug release. In cardiovascular applications, MNs maximize local anticoagulant effects, inhibit endometrial hyperplasia, and reduce systemic side effects. We speculate that a MN drug delivery system can be used to target transplanted veins to inhibit their thrombosis and reduce the incidence of perioperative myocardial infarction after CABG surgery. Therefore, this study developed a hyaluronic acid MN patch loaded with tirofiban and conducted preliminary physicochemical tests. The safety, efficacy, biocompatibility, and targeting of the MN system were evaluated using in vitro and in vivo experiments using a jugular vein transplantation model. The results indicate that the MN system has excellent physical properties, safety, effectiveness, biocompatibility, and strong targeting, which can effectively inhibit early local thrombus formation. In addition, the observation of early postoperative endometrial hyperplasia activation provides a foundation for future research.&#xD.

An Investigation into the Effects of Varying Seasons, Indole-3-Butyric Acid (IBA) and Rooting Media on the Rooting and Longevity of Air-layered Water Apples (Syzygium samarangense L.)

Background: The variation observed in sexual propagation often results in slow growth and fruit development, attributed partly to insufficient photosynthates during early growth stages. To address this challenge, vegetative propagation methods such as air layering offer promising solutions. This technique not only accelerates productivity but also enhances the quality of water apples. Recognizing the importance of air layering in water apple cultivation, this experiment was conducted to standardize this technique by examining the impact of different seasons and planting media in the western tropical wet and dry climate of Tamil Nadu. Methods: The study was conducted to evaluate the variables affecting air layering in water apples in Coimbatore district. The experiment was carried out with three different factors like seasons [August (S1), September (S2) and October (S3)] and IBA [applied at different concentrations of 2000 mg/L (I1), 3000 mg/L (I2) and 4000 mg/L (I3)] along with different rooting media: Cocopeat (M1) and Sphagnum moss (M2). The factorial randomized complete block design (FRCBD) was laid out for statistical analysis. Result: Sphagnum moss performed as a better rooting medium due to its high water holding capacity and good aeration. Increase in the number and early formation of roots were due to more rain fall and high relative humidity in August, that resulted in more nutrient uptake and structural stability. The discovery aids in determining the optimal conditions, including season, dosage and combination (4000 mg/L IBA with sphagnum moss applied in August), for successful air layering in water apple.

Ultrafast thermal modulation dynamics during ripple formation induced by a femtosecond laser multi-pulse vortex beam

Abstract This work theoretically investigated the ultrafast thermal modulation dynamics during early formation of ripples on an Au film induced by femtosecond laser multi-pulse vortex beam irradiation. An extended two-temperature dynamics model that comprehensively considers optical interference modulation for the formation of seed ripples, transient reflectivity and non-equilibrium thermal transfer was self-consistently built to predict high-contrast ripple formation. The two-dimensional evolution of electron and phonon temperature modulations during ripple formation in a high non-equilibrium state of Au film were obtained via femtosecond laser multi-pulse vortex beam irradiation. It was revealed that ripple contrast can be significantly amplified by shortening the laser wavelength, increasing the pulse number, or enlarging the laser fluence of the vortex beam. Moreover, the electron–phonon coupling time during ripple formation is fully explored in detail. This study provides valuable insights into optimizing laser parameters for controlled high-contrast ripple formation on Au films.

Reactivity of chondritic meteorites under H2-rich atmospheres: Formation of H2S.

Abstract Current models of chemical evolution during star and planetary formation rely on the presence of dust grains to act as a third body. However, they generally ignore the reactivity of the dust grains themselves. Dust grains present in the protoplanetary phase will evolve as the solar system forms and, after protoplanets have appeared, they will be constantly delivered to their surfaces in the form of large aggregates or meteorites. Chondritic meteorites are mostly unaltered samples of the dust present in the first stages of the Solar System formation, that still arrive nowadays to the surface of Earth and allow us to study the properties of the materials forming the early Solar System. These materials contain, amongst others, transition metals that can potentially act as catalysts, as well as other phases that can potentially react in different astrophysical conditions, such as FeS. In this work, we present the reactivity of chondritic meteorites under H2-rich atmospheres, particularly towards the reduction of FeS for the formation of H2S and metallic Fe during the early phases of the planetary formation. We present the obtained results on the reaction rates and the percentage of FeS available to react in the materials. Additionally, we include a computational study of the reaction mechanism and the energetics. Finally, we discuss the implications of an early formation of H2S in planetary surfaces.

A kiloparsec-scale ordered magnetic field in a galaxy at z=5.6

Magnetic fields are widely observed in various astronomical contexts, yet much remains unknown about their significance across different systems and cosmic epochs. Our current knowledge of the evolution of magnetic fields is limited by scarce observations in the distant Universe, where galaxies have recently been found to be more evolved than most model predictions. To address this gap, we conducted rest-frame 131\,mu m full-polarisation observations of dust emission in a strongly lensed dusty star-forming galaxy, SPT0346$-$52, at $z=5.6$, when the Universe was only 1 Gyr old. Dust grains can become aligned with local magnetic fields, resulting in the emission of linearly polarised thermal infrared radiation. Our observations have revealed a median polarisation level of $0.9 percent with a variation of $ percent across the 3\,kiloparsecs extention, indicating the presence of large-scale ordered magnetic fields. The polarised dust emission is patchy, offset from the total dust emission and mostly overlaps with the C\ ii $. The bimodal distribution of field orientations, their spatial distribution, and the connection with the cold gas kinematics further emphasise the complexity of the magnetic environment in this galaxy and the potential role of mergers in shaping its magnetic fields. Such early formation of ordered galactic magnetic fields also suggests that both small-scale and large-scale dynamos could be efficient in early galaxies. Continued observations of magnetic fields in early galaxies, as well as expanding surveys to a wider galaxy population, are essential for a comprehensive understanding of the prevalence and impact of magnetic fields in the evolving Universe.

Crack Development and Electrical Degradation in Chromium Thin Films Under Tensile Stress on PET Substrates

The mechanical and electrical deterioration of chromium (Cr) thin films sputtered onto polyethylene terephthalate (PET) substrates under tensile strain was studied. Understanding mechanical and electrical stability due to imposed strain is particularly important for device reliability, as the demand for flexible electronic devices increases. Cr thin films, widely spread across the field of electronic and sensor applications, face crack propagation with electrical degradation with tensile stress that can seriously compromise the performance. Accordingly, this study offers new findings on how Cr film thickness might influence crack formation and electrical resistance differently and also the general guidelines for flexible electronic component design with respect to long-term durability. Electrical resistances were measured while mechanically stretching 100- and 200 nm thin sheets. The study focused on crack development and propagation mechanisms in both film thicknesses and their effects on percentage change in electrical resistance (PCER). Scanning electronic microscopy (SEM) was used to characterize surface morphology and observe cracks as the strain rose. Early crack formation in 100 nm Cr films led to rapid PCER increases due to quick crack propagation and fast electrical degradation. Thicker 200 nm films, however, showed a more gradual PCER rise with fewer but deeper cracks, indicating a regulated strain response. Unlike the sharp PCER spike in 100 nm films, 200 nm samples were more variable, with three out of four showing a slight PCER decrease at the end, hinting at partial crack repair or conductive realignment before full failure. These results underscore the role of layer thickness in managing crack propagation and electrical stability, relevant for flexible electronics and strain sensors. This paper is aligned with the ninth goal of the United Nations Sustainable Development Goals, specifically Target 9.5: Enhance Research and Upgrade Industrial Technologies.

Analysis of lake level fluctuations in the Early Cretaceous Songliao Basin supports aquifer eustacy

Clear geochronology and precise interpretation of sequence stratigraphy enhance our understanding of continental lake-level evolution. The Songliao Basin features well-preserved Cretaceous continental strata. Nevertheless, the correlation between lake-level fluctuations and global sea-level changes remains ambiguous. High-resolution gamma ray logging data were used to analyze the cyclical stratigraphy of the lower member of the Early Cretaceous Shahezi Formation in the Songliao Basin. X-ray fluorescence experiments characterized the sedimentary environment of this formation. Lake-level variations in the lower part of the Early Cretaceous Shahezi Formation were reconstructed using sedimentary noise modeling based on finely tuned gamma ray logging data. Time series analysis using the tuned gamma ray data established an astronomical timescale of approximately 2.4 Myr within the lower section of the early Cretaceous Shahezi Formation in the Songliao Basin. A volcanic ash layer dating (118.20 ± 1.5) Ma from the base of the Shahezi Formation served as an anchor point, providing an absolute astronomical timescale ranging from 115.80 to 118.20 Ma for the study region. The sedimentary model indicates that variations in paleowater depth within the lower section of the Shahezi Formation closely match fluctuations observed in the Fe/Mn index, which reflects paleowater depth changes. This introduces a novel approach to assess changes in continental lake levels. The sedimentary noise model revealed a notable obliquity cycle of about 1.2 million years, strongly associated with fluctuations in lake levels. This indicates that prolonged obliquity periods affect lake level variations. Intriguingly, when lake levels rise, global sea levels concurrently decline, highlighting an inverse relationship between these phenomena. This observation offers insights into how long-term obliquity-driven climate changes regulate sea and lake levels.

Anti-biofilm potential of red pitahaya betacyanins against Streptococcus mutans, Actinomyces viscosus and Aggregatibacter actinomycetemcomitans

This study investigated the antibiofilm effects of betacyanin fraction (BF) from red pitahaya against Streptococcus mutans, Actinomyces viscosus, and Aggregatibacter actinomycetemcomitans, key pathogens in oral biofilm formation. Betacyanin purification employed column chromatography, and characterization was performed using liquid chromatography-mass spectrometry. Crystal violet assay and scanning electron microscopy demonstrated significant inhibition of early biofilm formation and disruption of preformed biofilms using BF (0.94–15 mg/mL). Anti-adhesion assays on artificial teeth indicated potent betacyanin-mediated inhibition of both sucrose-dependent and -independent bacterial attachment. Notably, growth curve and pH drop assays revealed that BF hindered pH reduction for all tested bacteria without suppressing their growth. Tetrazolium-based cytotoxicity assays showed minimal toxicity towards normal human gingival fibroblasts (HGF-1) at 0.78–12.5 mg/mL. These findings demonstrate the potential of red pitahaya betacyanins as promising antibiofilm agents for oral health, targeting both initial and mature stages of biofilm development.

A novel Cdc42-YAP-fibronectin signaling axis regulates ameloblast differentiation during early enamel formation.

Enamel formation is a developmental event governed by intricate molecular signal pathways. Cdc42 is proven to regulate enamel development yet its underlying role and molecular mechanism in early amelogenesis remain elusive. The extracellular matrix of tooth germ basement membrane is critical for the regulation of ameloblast differentiation. Present study investigated whether Cdc42 influences amelogenesis by affecting ECM synthesis and how Cdc42 regulates ameloblasts differentiation. Epithelial-specific knockout of Cdc42 (Cdc42-cKO) mice model was employed to study the ECM expression including Fibronectin (Fn) and amelogenesis markers. Cdc42-cKO mice results in retarded ameloblast differentiation and enamel matrix decrease. Fn synthesis in the enamel organ and basal membrane was totally diminished along with Cdc42 knockdown. YAP acting as the Cdc42 downstream transcription factor, its distribution in ameloblasts was synchronously attenuated by Cdc42 knockdown and nuclear localization progressively decreased with tooth germ development. Cdc42 unidirectionally controls the Fn synthesis via YAP regulation. Overall, ameloblast differentiation inhibition by silencing of Cdc42 was successfully rescued by YAP activation. We demonstrated that Cdc42 as an initiator, mediated downstream pathway through transcriptional activator YAP, thereby affecting ameloblast differentiation by controlling Fn synthesis. The Cdc42-YAP-Fn signaling axis are elucidated to act critical role during the early amelogenesis.

A SPectroscopic Survey of Biased Halos In the Reionization Era (ASPIRE): JWST Supports Earlier Reionization around [O iii] Emitters

Understanding when and how reionization happened is crucial for studying the early structure formation and the properties of the first galaxies in the Universe. At z > 5.5, the observed intergalactic medium (IGM) optical depth shows a significant scatter, indicating an inhomogeneous reionization process. However, the nature of the inhomogeneous reionization remains debated. A SPectroscopic survey of biased halos In the Reionization Era (ASPIRE) is a JWST Cycle 1 program that has spectroscopically identified >400 [O iii] emitters in 25 quasar fields at z > 6.5. Combined with deep ground-based optical spectroscopy of ASPIRE quasars, the ASPIRE program provides the current largest sample for IGM-galaxy connection studies during cosmic reionization. We present the first results of IGM effective optical depth measurements around [O iii] emitters using 14 ASPIRE quasar fields. We find the IGM transmission is tightly related to reionization era galaxies to the extent that a significant excess of Lyα transmission exists around [O iii] emitters. We measure the stacked IGM effective optical depth of IGM patches associated with [O iii] emitters and find they reach the same IGM effective optical depth at least d z ∼ 0.1 ahead of those IGM patches where no [O iii] emitters are detected, supporting earlier reionization around [O iii] emitters. Our results indicate an enhancement in IGM Lyα transmission around [O iii] emitters at scales beyond 25 h −1 cMpc, consistent with the predicted topology of reionization from fluctuating UV background models.

The Ancient Star Formation History of the Extremely Low-mass Galaxy Leo P: An Emerging Trend of a Post-reionization Pause in Star Formation

Isolated, low-mass galaxies provide the opportunity to assess the impact of reionization on their star formation histories (SFHs) without the ambiguity of environmental processes associated with massive host galaxies. There are very few isolated, low-mass galaxies that are close enough to determine their SFHs from resolved star photometry reaching below the oldest main-sequence turnoff. The James Webb Space Telescope (JWST) has increased the volume for which this is possible, and here we report on JWST observations of the low-mass, isolated galaxy Leo P. From NIRCam imaging in F090W, F150W, and F277W, we derive an SFH that shows early star formation followed by a pause subsequent to the Epoch of Reionization, which is then later followed by a reignition of star formation. This is very similar to the SFHs from previous studies of other dwarf galaxies in the “transition zone” between quenched very-low-mass galaxies and the more massive galaxies that show no evidence of the impact of reionization on their SFHs; this pattern is rarely produced in simulations of SFHs. The lifetime SFH reveals that Leo P’s stellar mass at the Epoch of Reionization was in the range that is normally associated with being totally quenched. The extended pause in star formation from z ∼ 5 to 1 has important implications for the contribution of low-mass galaxies to the ultraviolet photon budget at intermediate redshifts. We also demonstrate that, due to higher sensitivity and angular resolution, observing in two NIRCam short-wavelength filters is superior to observing in a combination of a short- and a long-wavelength filter.

The Molecular Cloud Life Cycle. II. Formation and Destruction of Molecular Clouds Diagnosed via H2 Fluorescent Emission

Molecular hydrogen (H2) formation and dissociation are key processes that drive the gas life cycle in galaxies. Using the SImulating the LifeCycle of Molecular Clouds zoom-in simulation suite, we explore the utility of future observations of H2 dissociation and formation for tracking the life cycle of molecular clouds. The simulations used in this work include nonequilibrium H2 formation, stellar radiation, sink particles, and turbulence. We find that at early times in the cloud evolution H2 formation rapidly outpaces dissociation and molecular clouds build their mass from the atomic reservoir in their environment. Rapid H2 formation is also associated with a higher early star formation rate. For the clouds studied here, H2 is strongly out of chemical equilibrium during the early stages of cloud formation but settles into a bursty chemical steady state about 2 Myr after the first stars form. At the latest stage of cloud evolution, dissociation outweighs formation and the clouds enter a dispersal phase. We discuss how theories of the molecular cloud life cycle and star formation efficiency may be distinguished with observational measurements of H2 fluorescence with a space-based high-resolution far-UV spectrometer, such as the proposed Hyperion and Eos NASA Explorer missions. Such missions would enable measurements of the H2 dissociation and formation rates, which we demonstrate can be connected to different phases in a molecular cloud’s star-forming life, including cloud building, rapidly star forming, H2 chemical equilibrium, and cloud destruction.

Widespread Rapid Quenching at Cosmic Noon Revealed by JWST Deep Spectroscopy

Massive quiescent galaxies in the young Universe are expected to be quenched rapidly, but it is unclear whether they all experience starbursts before quenching and what physical mechanism drives rapid quenching. We study 14 massive quiescent galaxies ( log(M⋆/M⊙)>10 ) at z ∼ 2 selected from a representative sample of the Blue Jay survey. We reconstruct their star formation histories (SFHs) by fitting spectral energy distribution models to the JWST/NIRSpec R ∼ 1000 spectra. We find that massive quiescent galaxies can be split into three categories with roughly equal numbers of galaxies according to their SFHs: (1) relatively old galaxies quenched at early epochs; (2) galaxies that are rapidly and recently quenched after a flat or bursty formation history (depending on the assumed prior); and (3) galaxies that are rapidly and recently quenched after a major starburst. Most recently quenched galaxies show neutral gas outflows, probed by blueshifted Na i D absorption, and ionized gas emission, with line ratios consistent with active galactic nucleus (AGN) diagnostics. This suggests that AGN activity drives multiphase gas outflows, leading to rapid quenching. By tracing back the SFHs of the entire sample, we predict the number density of massive quiescent galaxies at z = 4–6: n = (1.5–6.0) × 10−5 Mpc−3. The two old massive quiescent galaxies in our sample appear to have extremely early formation and quenching (z ≳ 6) and are possibly descendants of early post-starbursts at z > 3. These galaxies still show neutral gas reservoirs and weak Hα emission, perhaps because the ejective AGN feedback that caused rapid quenching has weakened over time.

Structure Formation Through Magnetohydrodynamical Instabilities in Primordial Disks

The shear flow instabilities under the presence of magnetic fields in the primordial disk can greatly facilitate the formation of density structures that serve as seeds prior to the onset of the gravitational Jeans instability. We evaluate the effects of the Parker, magnetorotational and kinematic dynamo instabilities by comparing the properties of these instabilities. We calculate the mass spectra of coagulated density structures by the above mechanism in the radial direction for an axisymmetric magnetohydrodynamic (MHD) torus equilibrium and power density profile models. Our local three-dimensional MHD simulation indicates that the coupling of the Parker and magnetorotational instability creates spiral arms and gas blobs in an accretion disk, reinforcing the theory and model. Such a mechanism for the early structure formation may be tested in a laboratory. The recent progress in experiments involving shear flows in rotating tokamak, field reversed configuration (FRC) and laser plasmas may become a key element to advance in nonlinear studies.

Apachyus madseni (Dermaptera: Apachyidae) sp. nov. from the Ypresian Fur Formation of Denmark: the first fossil record of the enigmatic earwig family Apachyidae

We describe Apachyus madseni sp. nov. based on an almost complete fossil from the Fur Formation in northwestern Denmark. The fossil is the second Dermaptera species described from the early Ypresian Fur Formation and the first fossil representative of the enigmatic family Apachyidae. Today, Apachyidae are restricted to Central Africa, and the Orient from southern India to the Philippines and northern Australia. The new fossil thus represents not only a new addition to the fossil mo-clay fauna, but also a considerable expansion of the historical biogeographical ranges of Apachyidae.

Synergistic effect of antibiotics, α-linolenic acid and solvent type against Staphylococcus aureus biofilm formation.

A promising approach to the treatment of bacterial infections involves inhibiting the quorum sensing (QS) mechanism to prevent the formation and growth of bacterial biofilm. While antibiotics are used to kill remaining bacteria, QS inhibitors (QSIs) allow for antibiotic doses to be reduced. This study focuses on evaluating the synergy between gentamicin sulphate (GEN), tobramycin (TOB), or azithromycin (AZM) with linolenic acid (LNA) against the formation of an early Staphylococcus aureus biofilm. Minimum biofilm inhibitory concentration (MBIC) was determined using the resazurin reduction assay for all antibiotics and LNA. The reduction of biofilm mass was assessed using the crystal violet (CV) assay. We have also evaluated the effect of dimethyl sulfoxide with TWEEN (DMSO_T) on early biofilm formation. Synergy was determined by metabolic activity assay and fractional biofilm inhibitory concentration (FBIC). DMSO_T at a concentration of 1% enhanced early biofilm formation, but also decreased the doses of antibiotic needed to reduce the biofilm by up to 8 times. Adding LNA at a concentration of 32µg/ml or 64µg/ml allowed up to a 32-fold reduction of antibiotic doses for GEN and TOB and a 4-fold reduction for AZM. LNA's use in combination with various antibiotics could reduce their doses and help fight drug-resistant bacteria in the biofilm.

The transcription factor foxo3 regulates cardiac remodeling after myocardial infarction

Abstract Background Myofibroblast and myeloid cell differentiation following acute myocardial infarction (MI) are important for myocardial fibrosis but also cause adverse remodeling leading to cardiac dysfunction and heart failure. The transcription factor forkhead box O 3 (Foxo3) inhibits hypertrophic cardiac remodeling. We hypothesized that Foxo3, a key regulator of cell differentiation and immunity might inhibit differentiation of fibroblasts and myoloid cells and therefore cardiac fibrosis after MI. Methods MI was induced in Foxo3-/- and wild-type mice by permanent LAD ligation. Cardiac function was determined by transthoracic echocardiography. Cell differentiation was investigated by single nucleus RNA-sequencing (snRNA-seq). Moreover, transdifferentiation assays ex vivo were performed. Results Foxo3-/- mice showed significantly improved survival post- MI (p<0.01) that was in part due to reduced cardiac ruptures (p<0.05). TTE showed reduced LV function, cardiac output, and global strain 4 days post-MI in both groups of animals. However, LV function was significantly attenuated in Foxo3-/- mice 14 d post-MI while diastolic parameters indicated enhanced wall stiffness. snRNA-seq on day 4 post-MI revealed significantly increased numbers of myofibroblasts (p<0.05) transdifferentiating from Progenitor-like state fibroblasts and epicardial derived fibroblasts in Foxo3-/- mice. Myofibroblasts upregulated genes important for extracellular matrix structure and cell migration. Moreover, an upregulation of pro-fibrotic genes was observed in other fibroblast clusters in Foxo3-/- mice and corroborated by significantly elevated collagen type 1 and 3 as well as periostin protein expression. Mechanistically, fibroblasts from Foxo3a-/- mice exhibited enhanced Smad3 dependent myofibroblast marker expression after TGF-ß stimulation. Cell chat analysis indicated enhanced number of interactions and interaction strength of myeloid cells with fibroblasts in Foxo3-/- animals. In line with these observations, differences in cardiac myeloid cell differentiation characterized by reduced center-log ratios of cardiac resident macrophages (Lyve1hiMHCIIlo and Lyve1loMHCIIhi) and increase in monocyte-derived macrophages (Ccr2hi MΦ and Trem2hi MΦ) on day 4 post-MI that was enhanced in Foxo3-/- mice were determined. Differential gene expression patterns on day 4 in pro-inflammatory macrophages (Ccr2hi MΦ) showed upregulation of genes in the interleukin-12 pathway while reparative macrophages (Trem2hi MΦ) revealed an increased expression of genes for extracellular matrix proteins and ECM-collagen interactions in Foxo3-/- mice. Conclusion Our data identify Foxo3 as a master regulator of cardiac remodeling inhibiting myofibroblast and myeloid cell differentiation after acute MI, and suggesting that deficiency of Foxo3 promotes early scar formation but also contributes to adverse matricellular remodeling resulting in impaired cardiac function and enhanced fibrosis.

The impact of UV spectra on searches for extremely metal-poor stars: A study for future CSST observations

Extremely metal-poor (EMPs, [Fe/H] < −3.0) and carbon-enhanced EMP (CE-EMP, [Fe/H] < −3.0 and [C/Fe]> + 1.0) stars are crucial for understanding the chemical evolution and early formation of the galaxies. Current research on EMP stars is limited by small samples, and ultraviolet (UV) band spectra are lacking. The China Space Station Telescope (CSST) will provide high-quality, low-resolution spectra across wavelengths from near-ultraviolet to near-infrared, with a limiting magnitude of about 21 mag. These will help in identifying EMPs and CE-EMP candidates in the distant Milky Way and nearby galaxies. The present study first uses the simulated CSST spectra to quantitatively evaluate the contribution of UV band spectra in predicting [Fe/H], [α/Fe], and [C/Fe]. The results indicate that UV band spectra reduce the mean absolute error by 0.04, 0.04, and 0.03, respectively, with a σ of 0.02, 0.03, and 0.04, respectively. Further spectral analysis reveals that the EMP stars show unique spectral-line features in the UV band, with significant differences compared to stars of higher metallicity, which could help in identifying EMP stars. Additionally, we tested the impact of UV band spectra on identifying EMP and CE-EMP stars at different noise levels and find that models including UV band spectra improve the identification of EMP and CE-EMP stars in terms of accuracy, recall, and F1 score. At low signal-to-noise ratio (S/N), the model including the UV band achieves a recall of 0.94, significantly higher than the model without the UV band (Recall = 0.48), doubling the capability to identify EMP stars. As the S/N increases, the inclusion of the UV band maintains high recall. This suggests that UV spectra in future large surveys could reduce the risk of missing potentially interesting stellar candidates, ensuring a more comprehensive identification of all possible EMP and CE-EMP star candidates.

Early embryonic development of the German cockroach Blattella germanica

BackgroundEarly embryogenesis is characterized by dramatic cell proliferation and movement. In most insects, early embryogenesis includes a phase called the uniform blastoderm, during which cells evenly cover the entirety of the egg. However, the embryo of the German cockroach, Blattella germanica, like those of many insects within the super order Polyneoptera, does not have a uniform blastoderm; instead, its first cells condense rapidly at the site of a future germband. We investigated early development in this species in order to understand how early gene expression is or is not conserved in these insect embryos with distinct early cell behaviors.ResultsWe present a detailed time series of nuclear division and distribution from fertilization through germband formation and report patterns of expression for the early patterning genes hunchback, caudal, and twist in order to understand early polarization and mesoderm formation. We show a detailed time course of the spatial expression of two genes involved in the segmentation cascade, hedgehog and even-skipped, and demonstrate two distinct dynamics of the segmentation process.ConclusionsDespite dramatic differences in cell distribution between the blastoderms of many Polyneopteran insects and those of more well-studied developmental models, expression patterns of early patterning genes are mostly similar. Genes associated with axis determination in other insects are activated relatively late and are probably not maternally deposited. The two phases of segmentation—simultaneous and sequential—might indicate a broadly conserved mode of morphological differentiation. The developmental time course we present here should be of value for further investigation into the causes of this distinct blastoderm type.